2014 Reprint of 1931 Edition. Full facsimile of the original edition, not reproduced with Optical Recognition Software. This landmark among mathematics texts applies group theory to quantum mechanics, first covering unitary geometry, quantum theory, groups and their representations, then applications themselves - rotation, Lorentz, permutation groups, symmetric permutation groups, and the algebra of symmetric transformations. Hermann Weyl was one of the most influential mathematicians of the twentieth century. Along with his fundamental contributions to most branches of mathematics, Hermann Weyl (1885-1955) took a serious interest in theoretical physics. In addition to teaching in Zurich, Gottingen, and Princeton, Weyl worked with Einstein on relativity theory at the Institute for Advanced Studies. "A classic of physics . . . the first systematic presentation of Einstein's theory of relativity." - British Journal for Philosophy and Science